Tektronix 2200 series fan noise?

[Spawn]

As some of you remember I picked up a Tek 2221A 3 days ago, I played couple times with it in the living room and didn’t notice the fan noise.

Today I made some room for the Tek on the table in my hobby room and I wanted to see the output noise of my bench power supply in storage mode.
After couple minutes the fan noise made me crazy, in quiet environment it gets annoying after a while.

So I grabbed my old trusty Voltcraft multimeter with dB meter and measure the sound.
Sound difference was 17dB with Tek turned on.

Any other Tek 2200 series owners (with fan) are annoyed with this sound or does my fan need some lubrication?

I made a video of it, I know this multimeter is not exactly a good reference but it still measures, sensor of the meter was faced to me instead of the fan so it reads little bit lower.

[T4P]

Well that means the RPM is too high for it sound annoying .
You should either clean the fan bearings or get a replacement that spins slower/ sounds not so annoying at the same size but have the same CFM rating ( You decide the power rating as to how much has power tektronix left behind as spare for the fan . )

[Spawn]

Yes I understand that with the RPM Dave, the thing i want to find out is; is it same on others too, if so i can change the fan, if not i am going to lubricate it, to do so i have to lift up the sticker on the fan and i only want to do that if i am sure.

[BravoV]

My Tek 2465B's fan has the same identical noise too, these old fans in old analog tek scopes are aged enough to warrant a replacement or lubrication.

Pic of the fan from my teardown thread -> Tek 2465B Teardown

[wkb]

My Tek2465CTS has (still) a very quiet fan.  If it ever goes south, I will replace it with a low-noise computerfan.

And while we are discussing fan noise: you should hear my Tek 1240 logic analyser.  That one sounds more like a F15 warming up its engines.  Holy c*   I'll probably replace that fan with something more quiet, too annoying otherwise.

[Spawn]

[sarcastic mode]
Did I said sound? No there is no sound this thing is quiet as a graveyard!
[/sarcastic mode]

I open up to see the fan and it is build in the power supply, to get there I have to tear apart whole oscilloscope, I could still see the fan sticker from back so I piled off the sticker, there was enough oil/grease in there, I cleaned the old crap and lubricate it again.
Result? No more pitching sound but dB is still same or I am imagining things and there is still pitching sound.

I was surprised to see a Sunon fan in there, if it ever dies I will shuff a Papst in its place.

While it was open I took some photos:

[wkb]

Wow... unobtanium ASICs and hybrids    But then again, infant mortality should not be a problem anymore, and these things are pretty robust as long as you take sensible care and not abuse them

[Spawn]

lol wkb inbetween my posts i missed yours about Tek 1240 logic analyser being loud.

See video below, after reading your post I took another video, this topic was started about measuring output noise of my new 10A bench power supply after all, and believe me this power supply just takes off when it’s turned on.

I need to make a review, after that I will change the fan in that power supply for sure.

Power supply is turned on and off while getting a sample on the oscilloscope:

[sonicj]

noctua

[T4P]

Yeah ... Noctua gets my vote , makes your power supply look a little weird in the inside but hell , they draw similar power as most fans .
More air , less RPM , lower pitch and lower SPL

[alm]

I seem to remember that some Noctua fans had problems if there was any significant static pressure it has to work against, like when the air path is fairly high impedance (eg. tight fins of a heatsink). This might be something to look out for in a scope. I might also use ball-bearing fans instead of sleeve bearing, although they make more noise, since I don't want to replace the fan in my scope every few years.

In general there's a fairly close relation between rpm and air flow for a given fan size. Quieter fans may create less turbulence and have less bearing noise, but don't expect a 15 dBa (yeah right) 1000 rpm fan to have similar airflow to a loud 2500 rpm fan, no matter what the manufacturer claims. Unlike datasheets in electronics, specs for consumer-oriented fans tend to be very... creative.

It's not been updated for a while, but the information about silent fans on silentpcreview.com is the best I've found so far.

[Spawn]

Thanks for the heads up guys 

About Noctua fans; I couldn’t find a 60x60x25mm version and while I was searching I found out Noctua fans are not really high end fans, since I couldn’t find a 60x60x25mm version I couldn’t compare.

alm, that site looks great, but also there is not much information about 60mm fans, most tests and reviews are based on 80mm and 120mm fans or I totally missed one with 60mm.

I know for a fact that EBM Papst fans are great industrial fans with high value and lifetime. They don’t come cheap compared to other fans but they last longer and their airflow vs dB ratio is great.
In the past where I worked in a dusty environment we had around 80 computer fans for several CCTV OCR and Color and fill up controlling machines, most applications had Sunon fans but also some different brands, these oem fans died on us from 8 to 16 months machines where used 24/7 back than I did some research and we replaced all fans with EBM Papst and believe me we had never issues with failing fans anymore after several years we only had to replace 2 EBM Papst fans.

This was not a surprise to us because all high end rack mounts are equipped with EBM Papst (Rital etc.).

The sunon in my photo up there is indeed used in Tek 2200 series:
http://qservice.tv/vpasp/shopexd.asp?id=9698

Here a data sheet of 60x60x25mm EBM Papst fans:
http://www.farnell.com/datasheets/513716.pdf

[Kilroy]

I would strongly suggest staying as close as possible to Tek's original fans specs.

System resistance is usually fixed, and should be a calculated value based on the configuration of the enclosure and impedance (obstacles) induced by the system proper. This is normally the reference when considering static pressure values. Assuming Tek is on the ball, they will have specified a fan that has performance curve characteristics that result in optimum venting for the particular enclosure under consideration and undoubtedly reexamined when under load to verify proper venting is in fact taking place. One hopes so at any rate.

Since fans display certain predictable characteristics with respect to power, pressure and speed you kind of have to make sure there some due consideration given to *all* of these laws or you may substitute a fan whose cfm values in free space which fails to adequately vent the specific enclosure once the system is under load. Proper system resistance and load checks are not really a trivial matter for most of us so it seems a safer alternative to stick close to OEM replacement specs to assure that the original performance envelope is respected.

By way of review, power requirements can be expected to change with the cube of speed, so you are looking at approximately a 30% power increase/decrease for every 10% increase/decrease in fan speed in rpm. Flow and speed are linear, so a 10% speed increase/decrease can be relied upon to provide a subsequent result in flow. Pressure typically rises/falls with the square of speed.

If they are available, and often the really useful ones are not, carefully scrutinize any fan performance curves. More aggressive blade pitch/profile and lower fan speed can yield similar free space flow characteristics, when mated to the specific system resistance of the enclosure, it may be unable to achieve the same loaded performance. Low speed high cfm fans are normally best used in relatively low resistance systems or systems employing a complimentary inlet fan of some sort.

[Spawn]

Thanks for your write up Kilroy, I was also thinking about that, but in my opinion couple ohms difference won’t make big difference, because when your equipment warms up your values will change anyways, thats why most people wait 20 to 30 minutes before they measure important things, same goes actually for everything with electronics, when I calibrated temperature, humidity and weight equipments (some other equipment) we waited at least a hour to get a accurate reading, to let settle everything down , the thing is to get same air flow not too much but also not to less.

As you see on my picture and BravoV's picture the fans have same spec when it comes to power input (Watt) and current, so resistance is also same or at least very close to each other, so i have to get really close to that.

The thing is the 60x60x25mm fans are not widely sold, most are only 10mm or 15mm thick which will affect the flow, I am thinking to get a 1.9Watt Papst whenever the fan dies, but it could take while before the fan dies of course.

[sonicj]

About Noctua fans; I couldn’t find a 60x60x25mm version and while I was searching I found out Noctua fans are not really high end fans, since I couldn’t find a 60x60x25mm version I couldn’t compare.

i've been collecting, modding and maintaining fans in the quest for silence for a long time. noctua is a very different type of fan. while it wasn't designed for industrial use, i certainly wouldn't classify as not high end. they are excellent at what they do.

i replaced the 60mm fan in my rigol turbine oscilloscope with a Vantec Thermoflow temp controlled fan. link it starts out nearly silent, yet can move a good bit of air if need be. im usually done making measurements by the time the fan spools up to a noticeable level.

if you can fit a 60mm to 80mm adaptor, your choice of fans increases significantly. http://www.amazon.com/Cables-Unlimited-Adapter-FAN-ADAPT-UVG-Green/dp/B000234SNA
-sj

[BravoV]

The thing is the 60x60x25mm fans are not widely sold, most are only 10mm or 15mm thick which will affect the flow, I am thinking to get a 1.9Watt Papst whenever the fan dies, but it could take while before the fan dies of course.

Too bad you're not living around my neighborhood, other wise you could grab one of this for free  , have tons of these 1st tier quality industrial 60 x 25 mm fans, all NOS sitting gathering dust here.

Definitely that Sunon or Noctua are not in the same league with these bad boys.

Teaser pic attached.

[Spawn]

Sonicj, I am absolutely with you there, maybe I put my words wrong, of course noctua has to be a good brand otherwise they wouldn’t have a lot fans like yourself, I would be the last person who wouldn’t believe you guys here on a electronics forum about such a topic believe me.
But it is like multimeters, there are a lot good multimeters but at the end most of us go for a Fluke or even Gossen Metrawatt because of it is quality and I really don’t understand why such brand as Tektronix shuff some Sunon in there, Sunon has good quality fans too of course but still I would expect another (better brand) fan in there.

About fitting a 80mm fan in there; it is possible to make a fan duct and put it outside the power supply, I think it will never fit in the power supply self, but as you see in my second photo i can mount it outside between the back cover, I think there is enough room there to do so but the duct needs to be really thin an i need to trim some off the back cover, the thing is I like to mod things but not my perfectly looking aged scope, it’s hard to explain but I would like to keep it original.

BravoV, you want to make me crazy don’t you 
I know for a fact Enermax put that brand fans in their high end computer power supplies long time ago, when a standard not to bad power supply was like 100 euro’s those Enermax power supplies where like in the 500 – 600 range, even build was just porn to see on those power supplies compared to normal ones.

I don’t think I will change the fan in the Tek yet or I must get really annoyed with it.

First thing to replace a fan is the power supply once I do the review I will put some another fan in it, I understand 10A China power supply with 4 output transistors need to be cooled but this fan is just too loud.
I am waiting on some banana plug busses (female) I ordered other day, because the thing came with melt down plus (+) lead out of the box, they build a 10A power supply but they still put crappy 3A banana plug busses in there, it just stupid.
Probably the lead is molten while they where testing it but they didn’t even bother to change it before they packaged it. 

[elliott]

I really don’t understand why such brand as Tektronix shuff some Sunon in there, Sunon has good quality fans too of course but still I would expect another (better brand) fan in there.

What were the best brands 20 years ago when that scope was made? Considering that fan has outlived the scope's expected useful life, I'd think they made a pretty good choice.

I've got a 2221A also, great scope, I can't say I've ever considered replacing the fan, it makes some noise, but it isn't distracting.

[sonicj]

exactly, quiet fans are a relatively new market...

if it were mine, i'd already have a new fan on order.... but, if keeping it stock is reaalllllly that important, the existing fan can likely be serviced.  remove the label with a xacto & hairdryer. pop the c-clip off the rotor shaft. after that, you'll find either a brass sleeve, radial bearings or a combination of both. the sleeves can be lubed with a non petroleum lube like silicon or ptfe grease or oil. the bearings often can be cleaned and re-lubed or simply replaced. in your scenario, i would likely re-lube with a grease like tri-flow synthetic. replace any worn o-rings or add shims if needed and reassemble. re-apply the sticker and you're done. (mine usually get a fresh smiley face sticker  )
-sj

[Spawn]

elliott, they could get a Panaflo or like I mentioned couple times a Papst. But you are right, Sunon in here kept up for a while so yeah it was not bad choice at the end. (Still don’t like it's sound )

Sonicj, I could indeed service the fan, I already removed the sticker and put fine machine oil in there, the high pitch is less now. By keeping it stock I didn’t mean the fan, for a 80mm I have to trim the plastic back cover.

While I was watching the photos again there was a light bulb next to my head for a second I thought I found easier way to replace the fan, otherwise why would they cut a hexagon there instead of a round hole, I took the back cover off and remove the plastic fan holder and carefully turn the fan inside the power supply but the fan is just to big… If they cut the hexagon 0,5mm wider it could come out.

[T4P]

EBM-papst is my favorite and Noctua manufactures PC fans . ( They had the best ratings of any fans )
But in any case the tek doesn't make much noise , it's the power supply that is startling !

But for me if i were to change it would end up as a San-Ace 9SG1212P1G01 or a Delta PFB1212UHE . ( Not those SLOW types , the ones that sound like a jet )
If it was loud anyway ( i wouldn't mind ) , might as well change it to a loud but extremely powerful one , and rewire ( Those monsters draw 4amps ! )

[BravoV]

EBM-papst is my favorite and Noctua manufactures PC fans . ( They had the best ratings of any fans )
But in any case the tek doesn't make much noise , it's the power supply that is startling !

But for me if i were to change it would end up as a San-Ace 9SG1212P1G01 or a Delta PFB1212UHE . ( Not those SLOW types , the ones that sound like a jet )
If it was loud anyway ( i wouldn't mind ) , might as well change it to a loud but extremely powerful one , and rewire ( Those monsters draw 4amps ! )

Are you actually aware and understand what is thread talking about ? That is considered as a gibberish post.

Replacing a tiny 1.5 watt 60 mm x 25 mm thickness sized fan that is cooling an oscilloscope with those crazy 48 watt 120 mm x 38 mm thickness " fan that has 64 dB noise is just plain "STUPID".

[Spawn]

Dave.S buddy… mate… friend… listen, BravoV is right about his comment, I told you this before in another topic, you should read before you post.

 I am around since the bulletin boards (now day’s forums) are invented and this is not a joke, I know for a fact if someone has so many useless posts in a month time they are after post counts, and believe me that won’t get you anything.

If the posts made me smart or better person I would be ruling the world by now…

Read last 5 posts here and ask yourself why you never got answer

[T4P]

I was just talking rubbish , of course , who would want to replace a 1.5w fan with a 48w fan ? That's nuts .

[Spawn]